SCOTT DETROW, HOST:
The heat is on in Texas where a spring heat wave has broken May temperature records in some parts of the state, and that is not the only place where heat is an issue. According to the National Oceanic and Atmospheric Administration, the planet's 10 warmest years since 1850 have all occurred in the past decade, with 2024 being the hottest year on record so far. And experts say heat this early in the year can be especially risky. NPR's Climate Desk reporter Alejandra Borunda explains why.
ALEJANDRA BORUNDA, BYLINE: Adelita Cantu lives in San Antonio, Texas, where it is currently sweltering around 100 degrees, and it's humid, too.
ADELITA CANTU: So even though we maybe, like, hit 100, it's going to feel like 105, 106.
BORUNDA: Texans are definitely not strangers to heat, but Cantu is a public health nurse at the University of Texas Health, San Antonio, and she knows that heat like this is particularly dangerous when it comes early in the heat season. And it's not just Texas. This is increasingly a problem across the United States. Tess Wiskel's an emergency physician at Harvard University outside of Boston. She has seen the emergency room fill up during early season heat waves, even when the temperatures don't seem super high.
TESS WISKEL: You tend to see outdoor workers getting sicker faster, and we tend to see athletes and other people like that.
BORUNDA: Wiskel says that happens because people's bodies haven't yet gone through a process called acclimatization. That can take a couple weeks of heat exposure as bodies make some key changes.
WISKEL: It will sweat earlier to help cool you off when you're acclimatized. Your whole blood volume is going to change when you're acclimatized, and all of these things help protect you from heat.
BORUNDA: So early in the year, a lot of people's bodies haven't done that yet. That means a higher risk of heat exhaustion, heat stroke, even heart problems. A study from 2010 found that the risk of dying from heat during the first heat wave of the year was roughly doubled.
WISKEL: When you're at the beginning of the heat season, something that you might have been used to by the end of the summer or by the end of the heat season, your body is not yet prepared for.
BORUNDA: Climate change is making the heat season stretch longer and start earlier. The Southwest now sees nearly three weeks more above-average spring days than in the 1970s. Pat Kinney is a climate and health expert at Boston University.
PAT KINNEY: What we call the warm season is spreading out over more months. You know, it's not just, you know, June, July and August. It's like May, June, July, August and September, and maybe even further out, you know, in some places.
BORUNDA: Cantu is definitely worried about that issue, too - how long heat season is going to last.
CANTU: People thinking, oh, my God, this is only May, can you imagine what the summer will be? There's that - some of that, I don't say depression but sadness setting in as well. Oh, my God, this is going to be a long, hot summer.
BORUNDA: So for everyone in Texas and the rest of the country, it's time to start acclimatizing to the heat that's coming. Alejandra Borunda, NPR News. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.